Cathedral researchers get into Anthropic's sales, HR and IT systems through third-party software
Anthropic internal business systems (third-party sales, HR and IT software)
Researchers at Cathedral, a months-old security start-up, got into a limited set of Anthropic's sales, HR and IT systems while testing under Anthropic's external security (bug bounty) program, The Washington Post reported on Oct 26 2026. Cathedral's draft report says its AI agents found paths in through flaws in third-party admin and sales software in under 12 hours, reaching meeting transcripts, salary and job-offer details and Slack messages. Anthropic confirmed access to systems holding business contact details for some customers and partners and basic user account records, but says Claude conversations, source code and model weights were not reached. It says its monitoring flagged the activity, it cut off access the same day, disabled the affected third-party apps until their vendors fixed the flaws, and found no evidence anyone else exploited them. Anthropic also says Cathedral did not disclose all of its testing as the program rules require and overstated the national-security implications.
Why this severity: Confirmed access to internal business systems and some customer and partner contact data, but by researchers under a bug bounty, with no evidence of outside exploitation; Claude data, code and weights not reached
- Started
- Oct 26, 2026
Affected
Not published yet
Fixed in
No fixed release yet
Timeline2
The Washington Post reports that researchers at the security start-up Cathedral got inside Anthropic's internal business systems during testing under Anthropic's external security program, citing a draft Cathedral report that says AI agents found the way in through third-party admin and sales software in under 12 hours.
Anthropic confirms Cathedral reached a limited set of sales, HR and IT systems holding business contact details for some customers and partners and basic user account records; it says Claude conversations, source code and model weights were not accessed, that its monitoring flagged the activity and it cut off access the same day, and that it found no evidence anyone other than Cathedral exploited the flaws.
News & write-ups4
- Researchers at cybersecurity start-up Cathedral got inside AnthropicThe Washington Post · Oct 26, 2026
- AI Agents Found a Way Into Anthropic's Business Systems in Under 12 HoursDecrypt · Oct 27, 2026
- AI startup claims it hacked Anthropic in 12 hours, gains access to employee details and internal messagesTechRadar · Oct 28, 2026
- AI startup hacked Anthropic, gains access to employee details, internal messagesHacker News · Oct 29, 2026
Notes & caveats
The third-party products involved have not been named publicly, so other companies using the same software can't yet tell whether they are exposed. Cathedral says it notified those vendors. Anthropic and Cathedral disagree on how much of the data the agents could reach was actually viewed.
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